The carrion beetle Oxelytrum discicolle (Coleoptera: Silphidae) and the estimative of the minimum post-mortem interval in a forensic case in Brasília, Brazil

Abstract

Abstract The order Coleoptera is considered second highest in forensic importance in criminal cases involving violent death, because members of this order increase in richness and abundance as the decomposition process progresses. We present here the first Forensic Entomology (FE) case in Brazil where the carrion beetle, Oxelytrum discicolle (Coleoptera: Silphidae), was used to estimate the minimum post-mortem interval (m-PMI) in a forensic case. A female corpse, at an advanced stage of decomposition, was found on a deserted highway near Brasília/Brazil. The corpse was removed from the site, and insect samples were collected on and inside the corpse at the Forensic Medicine Institute of the Federal Police, following the specific FE protocols. The m-PMI was estimated considering two techniques, the pre-appearance interval (PAI) and the accumulated degree-days (ADD). The development stage of the larvae of O. discicolle allowed investigators to propose that this species was part of an earlier colonization, soon after death, with total length and prothorax width compatible with third instar larvae. Adult females of O. discicolle oviposited on the corpse at least 20 days before it was removed from the site where it was found, thus characterizing the m-PMI. This is the first case in which information on the development of the O. discicolle was used in a criminal investigation in Brazil.

Keywords

• Entomological evidence
• Forensic entomology
• Insect larvae
• PMI